1. Technical Field
The present invention relates generally to digital computers; and more particularly to a method and apparatus for detecting errors in human interface devices for communicating with digital computers.
2. Related Art
There are many user input devices for use with a digital computer, including standard keyboards, touchpads, mice and trackballs. In order to ensure accurate operation of a user input device, it is important to have a means to test operation of the circuitry in the device. Prior art methods for performing such tests are typically conducted at the factory at the time the device is fabricated. Some prior art testing techniques for keyboards and mice include direct testing of the actual device by electromechanical devices, such as robots. Other prior art techniques using testing algorithms are typically performed by electronic devices in the factory with no means to test the device once it has left the factory.
Wireless communication technology has advanced rapidly over the past few years and there has been rapid development of wireless technologies for providing communication between input/output devices and their “host” computers. These “wireless” input devices are highly desirable since they do not require any hard-wired connections with their host computers. However, the lack of a wired connection also requires that the wireless input devices contain their own power supply, i.e., that they be battery powered.
To extend the life of its batteries, a wireless input device often supports power saving modes of operation. For example, a wireless interface may include circuitry to provide for various levels of “power-down” modes to reduce power consumption when the device is inactive. When activity is detected, the interface circuitry will transition to a powered-up mode to facilitate communications between the user interface device and the computer and will then return to a power-down mode after a predetermined interval of inactivity of the user interface device.
When a wireless device transitions from one of the various power-down modes to powered-up mode, it is useful to perform a quick check of the circuitry to ensure that the device is in proper condition for error-free operation. Likewise, after a wireless device has been powered-down to change the batteries, it is important to perform a self-test of the device's circuitry after the device returns to a powered-up state. In both of these situations, it is essential that the test consumes minimum power.
Heretofore, there has not been any power-conserving method or apparatus that provides for effective testing of a user input device, such as a keyboard or mouse, once the device has left the factory. Thus, there is a need in the art for a method and apparatus for testing a user input device such as a keyboard or mouse while consuming a minimal amount of power, thereby allowing a wireless input device to operate in an error-free condition for an extended period on a single battery life.